THE GRANITIC ROCKS OF THE SIERRA NEVADA 143 



of it may be called biotite-granite-gneiss. Ilmenite was found 

 in the granite-gneiss, but not in the more massive granite. As 

 the granite-gneiss has, after shearing and compression, under- 

 gone recrystallization, the ilmenite may possibly be secondary. 

 At some points the crushing, shearing and recrystallization has 

 been so thorough that the original massive granite has been con- 

 verted into a moderately fine-grained gneiss. 



Analyses have been made of this granite collected at three 

 different points. These analyses show but slight variation in 

 composition. There is also given an average of these three 

 analyses, and from this the molecular composition has been cal- 

 culated. Analysis 164 is of a biotite-granite which is regarded 

 by Lindgren 4 as representative of the biotite-granite of Pyramid 



ANALYSES OF BIOTITE-GRANITE 



Analyst: ' Hillebrand. 'Valentine. 3 Steiger. 

 4 Am. Jour. Sci., Vol. Ill, 1897, p. 307. 



